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| Causes of Hearing Loss | |
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The hearing mechanism involves a mechanical (conductive) component and a nerve (sensorineural) component. Although problems in either component can produce hearing loss, the treatments are quite different and an accurate diagnosis is important. Conductive Hearing Loss Conductive hearing loss occurs when the sound does not reach the hearing nerve. Blockage in the ear canal, lesions of the tympanic membrane (eardrum) or problems with the ossicles (hearing bones) can all produce conductive hearing loss. Ear Canal Disorders: Wax (cerumen) impaction Congenital narrowing or absence Infections or narrowing (swimmer's ear) Eardrum (tympanic membrane) and Middle Ear Disorders: Inflammation (myringitis) Holes (perforations) Infection (Otitis media) Fluid (effusion) Ossicles (hearing bones) Disorders: Congenital (since birth) abnormalities Erosion (dissolved) by infection Fixation (lack of vibration) by abnormal bone such as Otosclerosis Nerve (Sensorineural) Hearing Loss Nerve (Sensorineural) Hearing Loss occurs when the nerve endings (hair cells) in the inner ear (cochlea), the main auditory (hearing) nerve, or the brain connections do not function properly to carry the electrical sound signals to the brain. Disorders causing nerve hearing loss: Congenital (birth) deformities of the nerve Noise damage Ototoxic (drug effect) Infections Auto-immune (body inflammation) Trauma (fractures) Age (presbycusis) Tumors (acoustic tumors) Meniere's Disease (inner ear fluid disorders) |
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